We were mounting our own configuration to
`/usr/share/nginx/html/config.json`, which is a symlink to
`/tmp/config.json`. So we effectively mount our file to
`/tmp/config.json`.
When starting:
- if Hydrogen sees a `CONFIG_OVERRIDE` environment variable,
it will try to save it into our read-only config file and fail.
- if Hydrogen doesn't see a `CONFIG_OVERRIDE` environment variable (the
path we go through, because we don't pass such a variable),
it will try to copy its bundled configuration (`/config.json.bundled`)
to `/tmp/config.json`. Because our configuration is mounted as read-only, it will
fail.
In both cases, it will fail with:
> cp: can't create '/tmp/config.json': File exists
Source: 3720de36bb/docker/dynamic-config.sh
We work around this by mounting our configuration on top of the bundled
one (`/config.json.bundled`). We then let Hydrogen's startup script copy
it to `/tmp/config.json` (a tmpfs we've mounted into the container) and use it from there.
- forego removing Docker images - it's not effective anyway, because it
only removes the last version.. which is a drop in the bucket, usually
- do not reload systemd - it's none of our business. `--tags=start`,
etc., handle this
- combine all uninstall tasks under a single block, which only runs if
we detect traces (a leftover systemd .service file) of the component.
If no such .service is detected, we skip them all. This may lead to
incorect cleanup in rare cases, but is good enough for the most part.
